Epidermidis Research Articles

Comparative analysis of pathogen structure in patients with PJI after primary total hip and knee arthroplasty.

Microbiological profile of pathogens causing periprosthetic joint infection (PJI) after primary total hip (THA) and knee (TKA) arthroplasty varies in different regions, clinics and even departments. The objective of this study was to analyze the pathogen structure in patients with PJI after primary THA and TKA and its influence on the effectiveness of the infection eradication after two-stage reimplantation. We collected the retrospective data of 364 patients-161 with PJI after primary TKA (113 treated in two stages 48 with failure after spacer implantation) and 203 patients with infected THA (127 after successful two-stage reimplantation and 76 with PJI recurrence after the first stage) within the time period from January 2012 to December 2017, treated with two-stage protocol in the single center. A comparative analysis of pathogen structure was performed between cohorts of patients with hip and knee PJI. A subanalysis was made between the subsets comprised from patients with successful two-stage treatment and the subsets with failure to treat the infection. Staphylococcus epidermidis was the most commonly identified pathogen in the full hip and knee cohorts: 30.1% and 32.5%, respectively. However, the percentage of methicillin-resistant Staphylococcus epidermidis (MRSE) among all S. epidermidis isolates was higher in the hip cohort-50% compared with 35% in the knee cohort (p = 0.073). Other coagulase-negative Staphylococci were more common to patients with PJI after primary TKA-10.3% compared with 5% (p < 0.02). Streptococcus sp. caused hip PJI in a larger percentage of cases than in knee PJI (p < 0.01)-7% and 2%, respectively (p < 0.01). Polymicrobial associations were significantly more common in hip PJI compared to knee PJI: 45.3% and 14% of cases, respectively (p < 0.001). The presence of polymicrobial infection significantly raised the risk of PJI recurrence [OR 2 (95% CI from 1.24 to 3.24)] in knee PJI patients and reduced the effectiveness of infection eradication from 73.9% to 47.8%. Comparative analysis showed significant differences in the structure of PJI pathogens in the hip and knee. These findings are useful when choosing treatment strategies and empirical antibiotics regimens, in the management of patients with PJIs after primary hip and knee arthroplasty.

Assessment of Microbial Quality and Aflatoxin Levels of Akpu and Garri Sold in Some Selected Markets in Makurdi, Benue State -Nigeria

Microbial and aflatoxin studies of garri and akpu cassava in Makurdi–Nigeria were assessed for microbial and aflatoxin levels. Total valuable bacteria counts (TVBC) of 1.0x105 (cfu/g) were recorded in garri in all the markets. Total valuable fungi counts (TVFC) of 2.0x105 (cfu/g) were also recorded in garri from North Bank and Kanshio markets while Wurukum garri had TVFC of 3.0x105 (cfu/g). No TVBC and TVFC were detected in the controlled garri. Akpu from North Bank, Kanshio and Wurukum markets had 3.6x105 (cfu/g), 6.5x105 and 3.2x105 TVBC, respectively; while TVFC were 2.0x105 for akpu purchased from North Bank and Kanshio markets. No TVFC were recorded in Akpu from Wurukum and the control. No coliforms were detected in either of the samples. 3 fungi isolates (Mucar spp, Candida and Aspergillus niger) and 3bacteria isolates (Staphylococcus aureus, staphylococcus albus and Bacillus subtilis) were isolated. 0.13 and 0.40 ppm aflatoxin were only found in garri sold in North Bank market and the control, respectively. Akpu sold in Wurukum recorded the highest aflatoxin level, 4.90 ppm. The presence of microbial isolates and aflatoxin in the samples pose major threats to the consumers. Adequate hygienic practices by these food product handlers are recommended.

Hemodialysis Catheter-related Infections: Incidence, Microbiology and Outcome 5 years of Dubai Hospital Experience

Background: The central venous catheters (CVC) has recently become a worldwide commonest technique for vascular access, however; prone to infection and associated with other complications more than other vascular access techniques, such as fistula or graft.&#x0D; Objective: To investigate the incidence, the types of micro-organism, the most sensitive and suitable antibiotics, the outcomes associated with CVC infection in chronic hemodialysis patients treated through tunneled CVC.in a single-center population.&#x0D; Methods: The records of hemodialysis patients from January 2012 to December 2016 were reviewed. Patients above 14 years of age, on hemodialysis via a permanent tunneled catheter at any time of the mentioned period, were included. The rate of CRBSI (Catheter-Related Blood Stream Infections) was calculated as density of incidence and reported per 1000 catheter days. Patient mortality was recorded.&#x0D; Results: In 5 years, a total of 73 episodes of CRBSI in 49 hemodialysis patients were recorded. 59.2% were male with a mean age of 53.57 years. 40.8% had end-stage kidney disease secondary to diabetic nephropathy. In all, 67.3% episodes grew Gram-positive isolates, among those staphylococci epidermidis (26.4%, n=19) and staphylococci aureus (25%, n=18) were the most common organism, whereas Klebsiella pneumonia (8.3%, n=6), Enterobacter cloacae (8.3%, n=6), pseudomonas aeruginosa (5.5%, n=4) and E.coli (5.5%, n=4) were the most common Gram-negative isolates. A total of 6 isolates were multidrug-resistant, which includes Klebsiella pneumonia, Citrobacter, and E. coli. Only 1 out of 18 staphylococci aureus cases were methicillin-resistant and 21% (n=6) of Gram-negative isolates were Extended-spectrum beta-lactamase (ESBL) producing organisms. The average hospital stay was 9 days (2-30 days). The hemodialysis catheter was removed for 19 (38.77%) patients and 4 (8.1%) patients expired due to septic shock despite catheter removal and being on appropriate antibiotics.&#x0D; Conclusion: The mainstay to reduce CRBSI would be ideal to avoid catheters or decrease the duration of catheters. This can be achieved through more aggressive counseling and fast-track protocols for AV Fistulae creation at the pre-dialysis stage.

The dual impact of Jordanian Ephedra alte for inhibiting pepsin and treating microbial infections.

Screening of phytochemical Ephedra alte crude extract by GC–MS and HPLC analysis indicated the presence of alkaloids, tannins, flavonoids, terpenoids, and phenolic acid in the extract. The total phenolic content of E. alte methanol extract was 39.43 mg of Gallic acid eq/g, crude E. alte with 56.74, and 2.42 µg Trolox equivalent antioxidant capacity (TEAC)/g of plant extract according to DPPH and FRAP assay, respectively. The antimicrobial activity of E. alte against Staphylococcus aureus, staphylococcus epidermidis, Escherichia coli, and Klebsiellaoxytoca demonstrated a mean zone diameter of inhibition ranging from 0 to 17 mm. The MIC of the extracts ranged from 0.5 to 1.0 mg/mL. E. alte extract inhibits pepsin enzyme activity with IC50 values of 213.67 µg/ml. This study revealed that E. alte extract has pepsin enzyme inhibitory, antibacterial, antioxidant activities. The current outcomes indicate that E. alte might be employed as a natural agent for managing GERD and infectious diseases.

Synthesis, Antibacterial Activity and DFT Calculation of Co(II) and Ni(II) Schiff Bases Complexes Derived from Acenaphthenequinon and Phenylenediamine

Tetradentate Schiff base ligands. L1= (2Z)-2,2((4-methyl-1,2-phenylene) bis (azoneylidine))) bis (acenaphthylene-1(2H)-one, L2=(2Z,2E)-2,2'-((4-nitro-1,2-phenylene) bis azoneylylidene)) bis azoneylylidene)) bis (acenaphthylen-1(2H)-one, L3= 6.6 (((1E,2E)-acenphthylene -1,2diylidene) bis (azoanylidene)) bis (3-methylaniline), and L4= 6,6'-(acenaphthylene-1,2-diylidene) bis (azoneylyidene)) bis (3-nitroanilin), type (N2O2) and (N4) donor atoms obtained from condensation of acenaphthylenequinone with 4-methyl or nitro-o-phenylenediamine (2:1) and (1:2) (quinone:amine) molar ratio for the first and second type respectively. These ligands were used to synthesis complexes in general molecular formula [MLnCl2], where M= Co(II) and Ni(II) and n=(1-4). The ligands and the complexes were characterized by (1H-NMR, UV-Visible and FTIR) spectroscopy, metal content, elemental analysis C.H.N, magnetic and conductivity measurements. The low conductivity values reveal the non-electrolytic nature for the new complexes. All complexes are hexa co-ordinate with (octahedral geometry). Evaluation biological activity for the compounds screened against Gram(-) bacteria (Escherichalcoli, Pseudoaerogenosa) and Gram(+) bacteria (Staphylococcus aureus, staphylococcus epidermidis) and the optimized structure for the compounds carried out by using DFT calculation..

Risk factors for preoperative nasal carriage of methicillin-resistant bacteria in total hip and knee arthroplasty patients

BackgroundThe present study aimed to identify risk factors for preoperative nasal carriage of resistant bacteria - MRSA methicillin-resistant Staphylococcus (S.) aureus, MRSE (methicillin-resistant Staphylococcus epidermidis), and MRCNS (methicillin-resistant coagulase negative staphylococci) in total hip and knee arthroplasty (THA and TKA) patients. MethodsNasal cultures were obtained from 538 patients before THA (262 primary and 26 revision) and TKA (241 primary and 9 revision). These were classified either as methicillin-resistant bacteria (group MR) or methicillin-susceptible bacteria (including culture-negative) (group MS). Patient characteristics were compared between these groups using logistic regression models. ResultsThe resistant bacteria were preoperatively present in 33.1% (178 patients) among all patients. MRSE, MRCNS, and MRSA were detected in 27.5% (148 patients), 3.7% (20 patients), and 1.9% (10 patients). In the unadjusted comparisons of the patient characteristics between the groups MR and MS, a significant difference was found in the percentages of diabetic patients (15.2% vs. 9.2%, P = 0.04); the association remained after the multivariable adjustment for possible risk factors (P < 0.001). In addition, the diabetic patients in the group MR showed a higher percentage of receiving insulin injection than those in the group MS (25.9% vs. 6.1%, P = 0.063), and their mean levels of HbA1c were significantly higher in the group MR than the MS (6.8% vs. 6.4%, P = 0.03). ConclusionsWe identified diabetes as a risk factor for the preoperative nasal carriage of resistant bacteria. Our results suggest that, in order to prevent a surgical site infection (SSI), extra care should be taken in performing joint arthroplasties for diabetic patients, especially using insulin and with high HbA1c levels (≥6.6%) prior to the surgical procedures.

Chemical Synthesis and Structure-Activity Relationship Study Yield Desotamide a Analogues with Improved Antibacterial Activity.

Desotamides A, a cyclohexapeptide produced by the deep-sea-derived Streptomyces scopuliridis SCSIO ZJ46, displays notable antibacterial activities against strains of Streptococcus pnuemoniae, Staphylococcus aureus, and methicillin-resistant Staphylococcus epidermidis (MRSE). In this study, to further explore its antibacterial potential and reveal the antibacterial structure-activity relationship of desotamides, 13 cyclopeptides including 10 new synthetic desotamide A analogues and wollamides B/B1/B2 were synthesized and evaluated for their antibacterial activities against a panel of Gram-positive and -negative pathogens. The bioactivity data reveal that residues at position II and VI greatly impact antibacterial activity. The most potent antibacterial analogues are desotamide A4 (13) and A6 (15) where l-allo-Ile at position II was substituted with l-Ile and Gly at position VI was simultaneously replaced by d-Lys or d-Arg; desotamides A4 (13) and A6 (15) showed a 2–4-fold increase of antibacterial activities against a series of Gram-positive pathogens including the prevalent clinical drug-resistant pathogen methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 8–32 μg/mL compared to the original desotamide A. The enhanced antibacterial activity, broad antibacterial spectrum of desotamides A4 and A6 highlighted their potential as new antibiotic leads for further development.

A comparative assessment of pomegranate extract, sodium hypochlorite, chlorhexidine, Myrrh (Commiphora molmol), tulsi extract against Enterococcus faecalis, Fusobacterium nucleatum and Staphylococci epidermidis.

Background:The presence of pathogenic bacteria, toxins and byproducts in the root canal system show a decisive part in success of endodontic therapy. Thus, the complete removal of this bacterium is highly desirable. Several intracanal medicaments were tried to disinfect the root canal before obturation.Aim:The present study was conducted to compare Pomegranate, sodium hypochlorite, Chlorhexidine, Myrrh (Commiphora molmol), tulsi extract against Enterococcus faecalis, Fusobacterium nucleatum and Staphylococci epidermidis.Settings and Design:Cross-sectional observational prospective study.Materials and Methodology:Aqueous extract of 20% pomegranate peel, 20% pomegranate peel, 0.2% CHX, 2.5% sodium hypochlorite, Tulsi extract and Myrrh (Commiphora molmol) was used as agent against E. faecalis, F. nucleatum and Staphylococci Epidermidis. Zone of inhibition and minimum inhibitory concentration (MIC) was calculated and compared using analysis of variance and Mann–Whitney test. The information was statistically evaluated with SPSS software version 20 with P < 0.05.Results and conclusion:The mean zone of inhibition against E. faecalis, F. nucleatum and S. Epidermidis was highest in chlorhexidine and sodium hypochlorite groups compared to herbal groups. MIC was least with group III followed by group II against all bacterial species (P < 0.05). Sodium hypochlorite found comparatively better followed by chlorhexidine and other agents against E. faecalis, F nucleatum and S. epidermidis.

Bivalent Ni(II), Co(II) and Cu(II) complexes of [(E)-[(2-methyl-1,3-thiazol-5-yl)methylidene]amino]thiourea: synthesis, spectral characterization, DNA and in-vitro anti-bacterial studies

The present work describes the preparation of bivalent Ni(II), Co(II) and Cu(II) complexes of [(E)-[(2-methyl-1,3-thiazol-5-yl)methylidene]amino]thiourea (MTHC) by mixing in 1:2 ratio of corresponding metal salt and Schiff base ligand in ethanolic medium. The prepared ligand and its complexes are confirmed using elemental analysis, magnetic moments, FT-IR, NMR, electronic and ESR spectroscopy techniques. The spectroscopic data reveals that metal complexes are in square planar in nature. In DNA binding studies, the higher intrinsic binding constants (Kb) of Ni(II), Co(II) and Cu(II) complexes are 2.713 × 106 M−1, 5.529 × 106 M−1 and 2.950 × 106 M−1 respectively, evident that complexes are avid binder with DNA base pairs. The moderate anti-bacterial activity (in-vitro) against staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli bacterial culture may be due to the high electron density of ligand which prevents the charge reduction of metal ion. In the presence and absence of H2O2, it is notified that there is no appreciable DNA cleavage activity of Ni(II) and Co(II) complexes except Cu(II) complex which is due to aprotonation in the medium.

Evaluation of the role of staphylococci in the pathomechanism of conjunctivitis

PurposeDetermination of the association between ica genes and phenotypic biofilm formation in staphylococcal isolates involved in conjunctivitis, their antibiotic resistance as well as detection of selected virulence characteristics: adhesion to epithelial cells and in vitro cytotoxicity.MethodsThe study included 26 Staphylococcus aureus (SA) and 26 Staphylococcus epidermidis (SE) isolates. The presence of icaAD genes and ica operon was determined by the PCR assay. Phenotypic biofilm formation was verified using the microtitre plate assay. Antibiotic resistance was performed using the disc diffusion method. Staphylococcal ability to attach to host cells was assessed by flow cytometry. Cytotoxicity on epithelial cells was evaluated by LDH assay.ResultsThe ica genes were detected in 26.9% of SE and in 42.3% of SA isolates. Only 15.3% of isolates (SE) were positive for both the icaAD and the ica operon. Phenotypically, 19.2% of SE isolates were strong biofilm producers, among which three were both icaAD- and ica operon-positive. About 26.9% of SA isolates were strong biofilm producers. Methicillin resistance (MR) was detected in 34.6% of SE and 26.9% of SA isolates. About 75% of MR isolates were multidrug resistant. SA isolates adhered to host cells more extensively than SE. SA isolates released higher level of LDH than SE.ConclusionsAdherence abilities were commonly observed in staphylococci associated with conjunctivitis. However, low prevalence of isolates positive for a complete and functional ica locus and low prevalence of strong biofilm producers was detected. SA adhered to a greater extent to eukaryotic cells than SE and were more cytotoxic.

Design, synthesis, and antibacterial evaluation of PFK-158 derivatives as potent agents against drug-resistant bacteria

Infections caused by antibiotic resistant bacteria are a major health concern throughout the world. It is well known that PFK-158 can enhance the antibacterial effect of polymyxin, but its own anti-bactericidal effect is rarely discussed. In order to investigate the anti-bactericidal effect of PFK-158 and its derivatives, PFK-158 and 35 derivatives were designed, synthesized, and evaluated for their antibacterial activities. Compounds A1, A3, A14, A15 and B6 exhibited potent antibacterial effect against both clinical drug sensitive and resistant Gram-positive bacteria, and they are 2–8 folds more potent than levofloxacin against Methicillin-resistant staphylococcus epidermidis (MRSE). A significant synergistic effect of these compounds and polymyxin against drug-resistant Gram-negative bacteria, which is similar to PFK-158 was also observed. The result can provided a new and broader prospect for the development of new medicine against drug-resistant bacteria.

P02.18 Indwelling Pleural Catheter Placement in a Large UK District General Hospital

Indwelling pleural catheters (IPC) have become the main stay for patient centred treatment of malignant pleural effusions. They can be inserted as day case procedures, have very low complication rates and improve quality of life. They also reduce inpatient length of stay in respect to the malignant effusion. We have an established pleural service and analysed our practice over 4 years. All the notes of patients requiring IPC insertion between 2015 and 2019 were reviewed. 159 patients had an IPC inserted. 130 had died; mean survival 162 days. Mean age was 72.3 years and 39% of patients were female (n=62). 78 IPCs were done for mesothelioma, 61 done for other malignancies (29 lung, 24 breast, rest varied : melanoma, prostate cancer, ovarian cancer, colorectal cancers amongst others). 20 were done for non-malignant indications such as fibrinous pleuritis, cardiac amyloidosis, effusions of unknown cause, liver cirrhosis, heart failure. 146 IPCs were inserted as a day case, the rest were already inpatients. IPCs are done in theatre with a one off dose of prophylactic antibiotics. Complications included 4 infections (3 of pleural space by staph epidermidis and gram negative bacilli, 1 of site: site infection by staph. aureus {MSSA} – 2.5% (lower than national average in the UK), 6 blockages- 3.8 %, requiring removal (less than national average) and 2 small pneumothoraces post insertion. 1 patient had fast AF and hypotension post insertion.13 patients had loculations requiring intervention (8%- lower than national average) with intra-fibrinolytics, All of these patients had died by the time of data collection and we have stopped this practice in light of recent evidence that palliative care is more apporpriate. 57 IPCs were removed (36%- at a national average) for spontaneous pleurodesis. We provide an safe and effective indwelling pleural catheter service. Our lower rates of infection might be due to prophylactic antibiotic usage and insertion in theatre.

Vescalagin and Castalagin Present Bactericidal Activity toward Methicillin-Resistant Bacteria.

Polyphenols have been extensively exploited in the biomedical field because of their wide range of bioactive properties and historical use as traditional medicines. They typically present antioxidant, antimicrobial, antiamyloidogenic, and/or antitumor activities. In particular, cork water extracts and their components, have been previously reported to present antioxidant and antiamyloidogenic properties. On the basis of this knowledge, we tested cork water extract (CWE), cork water enriched extract (CWE-E), vescalagin/castalagin (two of the main polyphenols present in CWE and CWE-E) for their antibacterial activity against four bacterial strains, namely, methicillin-resistant Staphylococcus epidermidis (MRSE), Staphylococcus aureus (SA), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (PA). Vescalagin and castalagin presented bactericidal activity against all the tested bacterial strains, in particular toward the methicillin-resistant ones, i.e., MRSA and MRSE, as well as the ability to inhibit the formation of biofilms and to disrupt preformed ones. Moreover, vescalagin/castalagin seem to modulate the normal assembly of the peptidoglycans at the bacteria surface, promoting the disruption of their cell wall, leading to bacterial cell death. We also demonstrate that vescalagin/castalagin can be loaded into alginate hydrogels to generate antibacterial biomaterials that are not toxic to eukaryotic cells.

Eficiência de sabonetes comerciais antissépticos contra bactérias patogênicas e análise dos rótulos

Os sabonetes em barra com ação antisséptica são destinados à limpeza de resíduos presentes no corpo, sua utilização tem crescido significativamente em decorrência da preocupação da população com determinadas doenças causadas por contaminação microbiológica. Com isso, têm surgido no mercado diferentes marcas de sabonetes garantindo a eliminação de 99,9% das bactérias. O objetivo deste estudo foi realizar a análise comparativa do pH, atividade antibacteriana e rótulos de 5 diferentes marcas de sabonetes antibacterianos em barra, identificados como A, B, C D e E. Realizou-se a determinação do pH com auxílio de pHmetro digital, e na análise microbiológica utilizou-se a metodologia de disco difusão, com o intuito de observar a presença ou ausência da multiplicação das bactérias Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus e Escherichia coli frente aos diferentes sabonetes testados. Durante a análise da rotulagem dos sabonetes foi avaliada a presença do requisito “composição”, exigido pela resolução vigente. Nos testes realizados constatou-se que o pH de todas as marcas testadas encontraram-se fora dos parâmetros estabelecidos. Na análise microbiológica observou-se que apenas a marca E, demonstrou efeito antisséptico frente às bactérias testadas. Os demais sabonetes apresentaram menor e até mesmo nenhum potencial de inibição do crescimento desses microrganismos. Os produtos analisados neste estudo apresentam em suas formulações duas substâncias ativas, o triclosan e o triclocarban, porém os mesmos podem ser nocivos para a saúde humana e meio ambiente, e induzirem a resistência bacteriana, por isso, alguns países já proibiram o uso destes ativos. Segundo os resultados obtidos é possível concluir que os rótulos presentes das embalagens destas diferentes marcas analisadas estão em desacordo com o estabelecido pelos fabricantes.

Comparative genomics and transcriptomics analyses provide insights into the high yield and regulatory mechanism of Norvancomycin biosynthesis in Amycolatopsis orientalis NCPC 2-48

BackgroundNorvancomycin has been widely used in clinic to treat against MRSA (Methicillin-resistant Staphylococcus aureus) and MRSE (Methicillin-resistant Staphylococcus epidermidis) infections in China. Amycolatopsis orientalis NCPC 2-48, a high yield strain derived from A. orientalis CPCC 200066, has been applied in industrial large-scale production of norvancomycin by North China Pharmaceutical Group. However, the potential high-yield and regulatory mechanism involved in norvancomycin biosynthetic pathway has not yet been addressed.ResultsHere we sequenced and compared the genomes and transcriptomes of A. orientalis CPCC 200066 and NCPC 2-48. These two genomes are extremely similar with an identity of more than 99.9%, and no duplication and structural variation was found in the norvancomycin biosynthetic gene cluster. Comparative transcriptomic analysis indicated that biosynthetic genes of norvancomycin, as well as some primary metabolite pathways for the biosynthetic precursors of norvancomycin were generally upregulated. AoStrR1 and AoLuxR1, two cluster-situated regulatory genes in norvancomycin cluster, were 23.3-fold and 5.8-fold upregulated in the high yield strain at 48 h, respectively. Over-expression of AoStrR1 and AoLuxR1 in CPCC 200066 resulted in an increase of norvancomycin production, indicating their positive roles in norvancomycin biosynthesis. Furthermore, AoStrR1 can regulate the production of norvancomycin by directly interacting with at least 8 promoters of norvancomycin biosynthetic genes or operons.ConclusionOur results suggested that the high yield of NCPC 2-48 can be ascribed to increased expression level of norvancomycin biosynthetic genes in its cluster as well as the genes responsible for the supply of its precursors. The norvancomycin biosynthetic genes are presumably regulated by AoStrR1 and AoLuxR1, of them AoStrR1 is possibly the ultimate pathway-specific regulator for the norvancomycin production. These results are helpful for further clarification of the holistic and pathway-specific regulatory mechanism of norvancomycin biosynthesis in the industrial production strain.

The effects of TGF-β1 on staphylococcus epidermidis biofilm formation in a tree shrew biomaterial-centered infection model

BackgroundTransforming growth factor-β1 (TGF-β1) has a wide range of biological functions. It antagonizes lymphocyte response, inhibits pro-inflammatory cytokines, and serves as a signal to turn off the immune response and inflammatory response. To study the correlation between TGF-β1 and T helper (Th)1/Th2 cytokine levels in tree shrews, and to explore the effects of different levels of TGF-β1 on central venous catheter (CVC)-centered Staphylococcus epidermidis biofilm formation in tree shrews.MethodsTree shrews were injected with different concentrations of TGF-β1, and venous blood was drawn after 48 h to measure the levels of Th1 and Th2 cytokines. A CVC was placed into the femoral vein, and TGF-β1 at different concentrations and PIA− (ATCC12228) and PIA+ (ATCC35984) standard strains of Staphylococcus epidermidis were injected into the tree shrews to establish a biomaterial-centered infection (BCI) model. After 72 h, the CVC was removed, and biofilm formation was detected using the API bacterial identification system, semi-quantitative biofilm formation assay, and scanning electron microscopy.ResultsIn the groups treated with TGF-β1 at different concentrations, the levels of Th1 cytokines interleukin-2 (IL-2), tumor necrosis factor (TNF), and interferon-γ (IFN-γ) were lower than those of normal group, while the levels of Th2 cytokines IL-6, IL-4 and IL-10 were higher than those of normal group. In the TGF-β1 groups at different concentrations, the positive rate of Staphylococcus epidermidis ATCC35984 biofilm formation was higher than that in non-TGF-β1 group, while there was no significant difference in the positive rate of Staphylococcus epidermidis ATCC12228 biofilm formation compared with that of the non-TGF-β1 group.ConclusionsTGF-β1 causes the imbalance of Th1/Th2 cytokines and Th1/Th2 shift in tree shrews, leading to Th1 cell-led decline in cellular immune function. TGF-β1 promotes PIA+ Staphylococcus epidermidis biofilm formation in the tree shrew BCI model, but it has no significant influence on PIA-Staphylococcus epidermidis biofilm formation on the surface of CVCs.

Evaluation of the stability and antibacterial activity of crude extracts of hydro-endophytic fungi

The production and screening of secondary metabolites of four hydro-endophytes isolated from lotus, and the stability of bioactive compounds was evaluated. Surface-sterilized technique was used to isolate the endophytic fungi (EF) on potato dextrose agar and identified by using morphological and molecular techniques. The extracts were tested for anti-microbial activity against methicillin-resistant Staphylococcus aureus (MRSA) DMST20651, Streptococcus mutans (SM) DMST18777, Staphylococcus epidermidis (SE) ATCC12228, Pseudomonas aeruginosa (PA) TISTR1467, and Propionibacterium acnes (PN) DMST14916. The bacteriostatic and bactericidal activities were determined. Finally, thermal and ultraviolet (UV) stability was evaluated. Four endophyte isolates (EF 14, EF36, EF53, EF58, and EF60) produced secondary metabolites and showed activity against MRSA, SM, SE, PA, and PN, respectively. The crude ethyl acetate (EtOAc) and methanol (MeOH) extract of EF14 showed activity against MRSA with the inhibition zone of 9.00 ± 0.00 and 7.50 ± 0.50 mm, and minimum inhibitory concentration was 4.80 and 4.90 mg/mL, respectively. The minimum bactericidal concentration was 9.60 mg/mL. Whereas, the crude EtOAc and MeOH extract EF60, which were extracted by EtOAc and MeOH, showed inhibition zone of SE as 12.33 ± 0.57 and 12.33 ± 0.57 mm, respectively. Crude EtOAC extracts of EF14 showed highest thermal stability at 55°C–121°C, and UV stability with MRSA and SE, respectively. The results showed that the EtOAc extracts of EF could be potential antibacterial pathogens and displayed UV-thermal stability. This information is beneficial for future investigations, since some bioactive compounds have potential as anti-resistant strains of some bacterial pathogens.

Synthesis and characterization of CNC-cefexime nanohybrid as a potential antibacterial agent

This work concludes the synthesis of cellulose nanocrystal (CNC) using filter paper as a synthon for cellulose nanocrystal. Furthermore, this nanomaterial was used for the synthesis of new nanohybrid (CNC-cefixime) by the reaction of CNC with cefixime. CNC and its derivative were characterized using FTIR, XRD and SEM. The characterization results prove that cefixime was successfully functionalized on the surface of CNC. Moreover, the biological activity of the prepared nanomaterials were examined against four bacteria strains (Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Klebsilla sp). The results prove that CNC have no biological activity while CNC-cefixime shows an ability for the inhibition of Escherichia coli, staphylococcus epidermidis and klebsilla sp. with no effect against Staphylococcus aureus.

Analytical Study of Conjunctival Bacterial Flora in Diabetic and Non Diabetic Patients

Introduction: Conjunctiva is a transparent mucous membrane that lines inside of the eyelids and covers the sclera. It is composed of non keratinised, stratified columnar epithelium with goblet cells. Normal microbial flora constitutes organisms which are present in eyelids and conjunctiva without causing any disease. At birth eyes are sterile but they are later infected by various organisms. Gram positive organisms are mostly prevalent in ocular flora. Diabetes mellitus is a multifactorial disease that can affect all ocular structures. Aim: To compare the microbial flora between diabetic and non diabetic patients and to study there sensitivity to antibiotics. Materials and Methods: This was an analytical study conducted on a total of 100 patients attending Department of Opthalmology of Medical College and Hospital, Kolkata, India between June 2019 to July 2019. They were not using any topical ocular preparation. Conjunctival swab was taken from upper fornix of the patients and cultured and the results obtained were analysed using Chi-Square test. Results: Conjunctival flora of a total of 100 patients, 30 diabetic and 70 non diabetic, were screened. Among the 30 diabetic patients, there were 15 (50%) male and 15 (50%) female. The most common isolated bacteria in diabetic and non diabetic groups were staphylococcus aureus (diabetic 70%, non diabetic 85.7%). There was a statistically significant difference in microbial flora pattern between the diabetic and non diabetic group. There was higher proportion of staphylococcus epidermidis among diabetic patients compared to non diabetic patients (p-value &lt;0.01) and there was a higher proportion of staphylococcus aureus among non diabetics (p-value &lt;0.01). Conclusion: Present study found statistically significant difference in the microbial flora between diabetics and non diabetics. This will help the clinician to plan for the antibiotic prophylaxis before surgery for patients attending the Out Patient Department (OPD).

Analytical Study of Conjunctival Bacterial Flora in Diabetic and Non Diabetic Patients

Introduction: Conjunctiva is a transparent mucous membrane that lines inside of the eyelids and covers the sclera. It is composed of non keratinised, stratified columnar epithelium with goblet cells. Normal microbial flora constitutes organisms which are present in eyelids and conjunctiva without causing any disease. At birth eyes are sterile but they are later infected by various organisms. Gram positive organisms are mostly prevalent in ocular flora. Diabetes mellitus is a multifactorial disease that can affect all ocular structures. Aim: To compare the microbial flora between diabetic and non diabetic patients and to study there sensitivity to antibiotics. Materials and Methods: This was an analytical study conducted on a total of 100 patients attending Department of Opthalmology of Medical College and Hospital, Kolkata, India between June 2019 to July 2019. They were not using any topical ocular preparation. Conjunctival swab was taken from upper fornix of the patients and cultured and the results obtained were analysed using Chi-Square test. Results: Conjunctival flora of a total of 100 patients, 30 diabetic and 70 non diabetic, were screened. Among the 30 diabetic patients, there were 15 (50%) male and 15 (50%) female. The most common isolated bacteria in diabetic and non diabetic groups were staphylococcus aureus (diabetic 70%, non diabetic 85.7%). There was a statistically significant difference in microbial flora pattern between the diabetic and non diabetic group. There was higher proportion of staphylococcus epidermidis among diabetic patients compared to non diabetic patients (p-value&lt;0.01) and there was a higher proportion of staphylococcus aureus among non diabetics (p-value&lt;0.01). Conclusion: Present study found statistically significant difference in the microbial flora between diabetics and non diabetics. This will help the clinician to plan for the antibiotic prophylaxis before surgery for patients attending the Out Patient Department (OPD).